Method of synthesizing organosilicon compounds



United States Patent ABSTRACT OF THE DISCLOSURE .By employing buffer solutions,.addition of SiH-compounds to aliphatic unsaturated compounds in contact with chloroplatinic acid can be satisfactorily achieved in the presence of hydroxyl compounds such as water or alcohols.

This invention relates to the addition of SiH compounds to aliphatic unsaturated compounds in the presence of chloroplatinic acid.

One of the most versatile methods of'synthesizing organosilicon compounds involves the addition of an SiH containing compound to a compound containing terminal olefinic unsaturation. One of the best catalysts for this addition is chloroplatinicacid. The versatility of the reaction in the presence of this catalyst is shown in US. Patent 2,823,218.

It has been found, however, that the reaction of the SiH compound with olefinic unsaturated compounds employing chloroplatinic acid as a catalyst cannot be satisfactorily carried out in the presence of hydroxyl compounds such as water or alcohols. When such materials are present, a reaction occurs which in some cases is the predominant one. This reaction is as follows:

ESiH-l-ROH ESiOR-I-H This means that when chloroplatinic acid is the catalyst, one cannot satisfactorily add unsaturated alcohols to SiH compounds without an appreciable side reaction occurring. Also, one cannot employ alcohols as solvents for the reaction, nor can one tolerate water being present during the reaction. The latter can beparticularly annoying when one is adding polyalkylene oxides having terminal unsaturation to SiH compounds. Since the polyalkylene oxides are generally hydroscopic, one must carefully dry them prior to the reaction. This drying step is sometimes expensive and it would be advantageous to be able to add SiH compounds to terminally unsaturated polyalkylene oxides without the necessity of drying the reactants.

The above objections are eliminated by employing the method of this invention. t

This invention relates to a method of reacting in contact with chloroplatinic acid catalyst,-an SiH-containing compound with an organic compound containing terminal carbon-carbon unsaturation in the presence of a compound containing the hydroxyl group (i.e. alcohols and water), whereby addition of the SiH group to the carboncarbon unsaturation takes place, the improvement comprising carrying out said reaction in contact with a buffer solution, which in an aqueous system will in the presence of a strong acid maintain the system at a pH of from about 5 to about 7 inclusive.

The improvement employed in this invention consists in using the above defined bufler solution for carrying out the reaction in the presence of alcohols or water. Any bufier system which will maintain a pH between 5 and7 is operative herein. Specific examples of such buffers are mixtures of alkali metal hydroxides and potassium acid phthalate, sodium acetate, secondary sodium citrate; mixtures of potassium acid phosphate and disodium phosphate and mixtures of potassium acid phosphate and 3,398,174 Patented Aug. 20, 1968 "ice NaOH. Many other buffer compositions will be apparent to those skilled in the art. 7

The reaction of this invention is applicable to any organosilicon compound containing an SiH group and any olefinic compound containing a terminal carbon-carbon unsaturation, except those compounds which contain acidic groups such as carboxyl or sulfonic acid groups, or which when in the presence of alcohols or Water will produce strong acids. Thus, for example, the reaction is not operative withchlorosilanes or acyloxy silanes in generaLnor with organic compounds such as acyl halides or compounds containing readily hydrolyzable halogen atoms The organosilicon .and the organic olefinic compound can also not contain basic groups, such as amino or-quaternary ammonium groups, nor groupswhich will hydrolyze readily with water to produce a basic media.

Thus, for example, silazanes are not operative in this invention. In addition, the reaction will not proceed with acrylonitrile because platinum does not catalyze the addition of this material to SiH compounds.

Examples of operative organosilicon compounds which may be employed herein, are silanes such as SiH R SiH,

r Hsi(oR)r, HSi(OR)2, HSiO R and H Si(OR) silanes of the formula Ilia. HSi(ON=C R'2)un in which n is 0, 1 or 2, and siloxanes of the unit formulae HSiO H SiO,

1'1 Hsiofi in which at is 1 or 2, and copolymers of said siloxanes with siloxanes of the unit formula Rmsio in which m is 0, 1, 2 or 3. In any of the silanes or siloxanes above, R and R can be any organic radical (which is free of acidic or basic groups) such as hydrocarbon radicals such as methyl, ethyl, octadecyl, vinyl, allyl, cyclohexyl, cyclohexenyl, vinylcyclohexyl, methylcyclohexyl, phenyl, xenyl, tolyl, naphthyl, anthracyl, benzyl, and beta-phenylpropyl; any halohydrocarbon radical such as chloromethyl, gamma-chloropropyl, trifiuoropropyl, C F CH CH bromocyclohexyl, alpha,alpha,alpha-trifluorotolyl, perfiuorovinyl, chlorophenyl, bromoxenyl, para-chlorobenzyl and pentachloroxenyl; substituted hydrocarbon radicals such as hydrocarbon ether radicals such as CH CH OCH CH OCH hydrocarbon ester radicals such as CH CH CH OOCCH hydroxylated radicals such as CH CH CH OH; amide radicals such as and Dil'IlIO radicals such as CH CH CN, and radicals containing carbonyl groups such as CH C H CH CO.

The olefinic compound employed herein can be any organic compound having a carbon-carbon double bond in the terminal position. This includes organosilicon compounds which means that both the SiH compound and the compound containing the unsaturation can be organosilicon compounds and, in fact, the hydrogen and the olefinic group can be attached to the same silicon atom as is shown in the examples below. In addition to unsaturated organosilicon compounds the olefin compounds can be olefinic hydrocarbons such as ethylene, butylene, octadecylene, vinylcyclohexene, styrene, vinyltoluene, divinylbenzene and butadiene; unsaturated alcohols such as allyl alcohol; unsaturated ethers such as methylvinylether,

methylallyl ether, the allylether of trimethylolpropane, v

the monoallylether of glycerin, and the triallylether of glycerin; unsaturated esterssuch as vinylacetate, allylacetate, methylmethacrylate, butylmethacrylatewand allylbenzoate; unsaturated haloolefins such as vinyl chloride, allyl chloride, methallyl chloride, chloroprene, trifiuoroprene, and chlorostyrene; unsaturated amides such as acryl amide, N,N-dimethylacrylamide, and unsaturated aldehydesand ketones such as allylmethylketone, and acrolein. p n i The reaction of this invention can be carried out under the normal conditions for adding SiH compounds to olefins in the presence of chloroplatinic acid. The temperature required can range from room temperature up to 150 C. or above, but, in general, the reaction proceeds at temperatures below the latter temperature. The amount of butter solution and catalyst is not critical so long as there is sutlicient butter solution to maintain the pH in the specified range and so long as there is sufiicient catalyst to make the reaction go in a reasonable time.

The following examples are illustrative only and should not be construed as limiting the invention which is properly delineated in the appended claims. In the formulae shown below the following abbreviations are used pH for phenyl, Me for methyl, and Et for ethyl.

Example 1 The butter solution employed in this example was made by mixing 23.8 ml. of .2 Normal NaOH and 50 ml. of .2 M potassium acid phthalate. This solution has a pH of 5. 0.1 mole of vinyldiphenylsilane was mixed with 140 ml. of t-butanol, 7 ml. of the buffer solution and chloroplatinic acid in the amount of 2.8 g./atoms of platinum per mole of SiH. The mixture was allowed to stand at room temperature for 24 hours. A good yield of the polymer of the formula was obtained.

Example 2 .15 mole of phenyldimethylsilane and .15 mole of vinyltrimethylsilane were mixed with 140 ml. of butanol, 10.5 ml. of the bufifer solution of Example 1 and chloroplatinic acid in the proportion employed in Example 1 and the mixture allowed to stand at room temperature for 42 hours. An 80% yield of phMe SiCH CI-I SiMe was obtained.

Example 3 .1 mole of phenyldimethylsilane, .1 mole of allyl alcohol was mixed in 140 ml. of t-butanol, 7 ml. of the butter solution of Example 1 and chloroplatinic acid in the amount shown in that example and allowed to stand at room temperature for 46 hours. An excellent yield of the silane phenyldimethyl(gamma-hydroxypropyl)silane was obtained.

This experiment was repeated except that the butter solution was omitted; Instead of the desired product, the following materials were'obtained in amounts totaling 87.5% of theory. Phenyldimethylallyloxysilane Phenyldimethylpropoxysilane Phenyldimethyltertiarybutoxysilane 1 Example 4 .1 mole of l,l,3,3-tetramethyll-ethyldisiloxane was mixed with ml. of allyl alcohol, 7 ml. of the butter solution of Example 1, and chloroplatinic acid in the amount of 2.8x 10- g./ atoms of platinum per'rnole of SiH. The mixture was allowed to stand at 31-45 C. for 19 hours, and an excellent yield of the compound 1,l,3,3- tetramethyl 1 ethyl 3 (gamma hydroxypropyl) disiloxane' was obtained.

Example 5 The bufier solution employed in this example was a .1 molar solution of sodium acetate in ethanol. This solution has a pH of about 5.5.

. .1 mole of l,1,3,3-tetramethy1-l-ethyldisiloxane was mixed with .2 mole of l-butene-B-ol, .5 ml. of the butter solution and chloroplatinic acid in the amount of 4x10 g./atoms of platinum per mole of SiH and the mixture was heated at C. for 18 hours. There was obtained a good yield of. the compound 1,1,3,3-tetramethyl-l-ethyl- 3-(3-hydroxy-3-methylpropyl)disiloxane.

Example 6 Example 8 Employing the butter solution of Example 5, the following compounds can be prepared. I

Silicon Compound Product Olcfms OH Monoallyl ether of glycerin HSKOEt); HO CHaCIHCHiO (CHz)2Si(OEt)3 Me v 0 Me I Allyl glycldyl ether in ethanol HS i(OMe)a (filklHCHiO (CH S i(OMe)g Allyl alcohol Copolyrner ot- Copolymer 01- n p Me 10 mol ercent MeSiiO 10 mol percent HO(CH:)iS i0 40 mol percent MegSiO 40 mol percent MezSiO 40 mol percent PhMoSiO 40 mol percent PhltieSiO Q 10 mol percent PhSiOn a 10 mol percent PliSiO I llonoal yl other of ethylene glycol Copolymer ot' Copolymer ot V: 1

10 mol percent HsiO1-5 10 mol percent; HOCHaCHzWCHaliSiO Z 20 mol percent CnHnSiOns 20 mol percent @SiO mol percent CnHm-SiOm Olefins Silicon Compound Product Me Me Me Me 20 mol percent O/HOHQS iO 20 mol percent CHZS iO Me Me 20 mol percent CF3CH2CHz SiO 20 mol percent CF CHzOHzSiO Me 10 mol percent ClCuH4S iO 10 mol percent ClCfiH4S iO Meg M82 Me; Me: Mez

Allyl lactate HSi(0Si)50 SiH CHgCHOHCOO(CH:)3OSl(OSi) Me: OSKCHMOO C CHOHCHs That which is claimed is:

ence of a strong acid, maintain the system at a pH of from 1. In the method of reacting in contact with chloro- 20 about 5 to about7 inclusive.

platinic acid catalyst an SiH compound with an organic compound containing terminal carbon-carbon unsaturation, except acrylonitrile, said SiH compound and organic compound being free of acid and basic groups and any group which will hydrolyze to produce acid and basic groups, whereby addition of the SiH group to the carboncarbon unsaturation takes place, the improvement comprising carrying out said reaction in the presence of water or an alcohol free of acid and basic groups and any group which hydrolyze to produce acid or basic groups with a buffer which is an aqueous system will, in the pres- UNITED STATES PATENTS 2/1958 Speier et a1. 260-4482 1/1961 Bailey 260-4482 XR 0 HELEN M. MCCARTHY, Primary Examiner.

P. F. SHAVER, Assistant Examiner. 

